Method of estimating multi-phase fluid properties in a wellbore utilizing acoustic resonance
First Claim
1. A method of analyzing a fluid within a wellbore comprising:
- providing a sensor that comprises, a housing, a resonant cavity in the housing, an inlet to the cavity, an outlet from the cavity, a diaphragm, and an electroactive material coupled with the diaphragm;
disposing the housing in a path of fluid flowing in the wellbore so that a portion of the fluid flowing in the wellbore flows from an annulus between the housing and walls of the wellbore, enters the cavity through the inlet, flows through the cavity, and flows back into the annulus through the outlet;
generating acoustic waves in the fluid flowing through the cavity by oscillating the diaphragm over a range of frequencies;
measuring electrical voltage and current across the electroactive material for the range of frequencies to obtain an electrical admittance spectra corresponding to the fluid flow;
obtaining shifts in resonant frequencies of electrical admittance spectra by comparing the admittance spectra of the fluid flow with a reference admittance spectra obtained without the fluid in the cavity;
obtaining an estimator equation generated by, (a) comparing a number of different simulated admittance spectra with the reference admittance spectra, where each of the different simulated admittance spectra represents simulated values of admittance obtained for a particular fluid disposed in the cavity having a known density and sound speed, and where the admittance spectrum for each particular fluid is decomposed into the real, imaginary, magnitude, and phase components over a resonance frequency bandwidth, (b) developing a set of functions that include shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, the differences in shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and products of shifts and differences in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and (c) utilizing the set of functions in a series of multi-regression statistical analyses to determine the estimator equation;
andestimating a property of the fluid by substituting the value of the resonant frequencies'"'"' shifts in electrical admittance spectra into the estimator equation.
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Abstract
A system and method of estimating properties of a wellbore fluid that directs the fluid through a cavity, and generates acoustic waves in the fluid while in the cavity. The acoustic waves are generated by oscillating an electroactive material over a range of frequencies. An electrical admittance spectra of the electroactive material is measured over the range of frequencies; where the electrical admittance spectra includes the magnitude, real, and imaginary components. Differences between the maximum values for each component and a vacuum electrical spectra are calculated, the differences are substituted into estimator equations to estimate the fluid properties. Electrical admittance spectra of the electroactive material was simulated for a series of known fluids flowing through the cavity, and a multi-regression statistical analysis was then used to derive the estimator equations.
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Citations
17 Claims
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1. A method of analyzing a fluid within a wellbore comprising:
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providing a sensor that comprises, a housing, a resonant cavity in the housing, an inlet to the cavity, an outlet from the cavity, a diaphragm, and an electroactive material coupled with the diaphragm; disposing the housing in a path of fluid flowing in the wellbore so that a portion of the fluid flowing in the wellbore flows from an annulus between the housing and walls of the wellbore, enters the cavity through the inlet, flows through the cavity, and flows back into the annulus through the outlet; generating acoustic waves in the fluid flowing through the cavity by oscillating the diaphragm over a range of frequencies; measuring electrical voltage and current across the electroactive material for the range of frequencies to obtain an electrical admittance spectra corresponding to the fluid flow; obtaining shifts in resonant frequencies of electrical admittance spectra by comparing the admittance spectra of the fluid flow with a reference admittance spectra obtained without the fluid in the cavity; obtaining an estimator equation generated by, (a) comparing a number of different simulated admittance spectra with the reference admittance spectra, where each of the different simulated admittance spectra represents simulated values of admittance obtained for a particular fluid disposed in the cavity having a known density and sound speed, and where the admittance spectrum for each particular fluid is decomposed into the real, imaginary, magnitude, and phase components over a resonance frequency bandwidth, (b) developing a set of functions that include shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, the differences in shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and products of shifts and differences in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and (c) utilizing the set of functions in a series of multi-regression statistical analyses to determine the estimator equation; and estimating a property of the fluid by substituting the value of the resonant frequencies'"'"' shifts in electrical admittance spectra into the estimator equation. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of analyzing a fluid within a wellbore comprising:
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a) diverting a portion of fluid flowing inside the wellbore into a cavity; b) creating standing waves in the fluid diverted into the cavity with a diaphragm that is oscillated by a piezoelectric stack; c) oscillating the piezoelectric stack over a range of frequencies by conducting electricity to the piezoelectric stack from a power source; d) monitoring an admittance across the piezoelectric stack over the range of frequencies to define a fluid admittance spectra; e) comparing the fluid admittance spectra with a reference admittance spectra that was generated by oscillating the piezoelectric stack over a range of frequencies with the cavity being empty, the admittance spectrum for each particular fluid is decomposed into the real, imaginary, magnitude, and phase components over a resonance frequency bandwidth; f) obtaining an estimator equation generated by, (i) comparing the reference admittance spectra with a number of simulated admittance spectra for different known fluids disposed in the cavity, the simulated admittance spectra for different known fluids represents simulated values of admittance obtained for a particular fluid disposed in the cavity having a known density and sound speed, (ii) developing functions that are dependent on a variation of resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and (iii) utilizing the functions in a series of multi-regression statistical analyses to determine the estimator equation; g) obtaining differences of maximum values of magnitude, real values, and imaginary values between the fluid admittance spectra and the reference admittance spectra; and h) estimating properties of the fluid by substituting the differences obtained in step (g) into the estimator equation of step (f). - View Dependent Claims (9, 10, 11)
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12. A fluid measurement system for analyzing fluid within a wellbore comprising:
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a sensor assembly comprising, a main body, a cavity in the main body in communication with fluid ambient to the sensor assembly, an inlet and outlet in the cavity so that a portion of fluid flowing in the wellbore into the cavity via the inlet, and back into the wellbore through the outlet; a solid piezoelectric stack in the main body that is selectively oscillated over a range of frequencies when energized, and a diaphragm coupled to an end of the piezoelectric stack and disposed in the cavity, so that the diaphragm oscillates in the cavity when the piezoelectric stack is oscillated; and a processor in communication with the sensor assembly that, selectively receives data representing an electrical admittance spectra associated with the fluid that is defined by monitoring an electrical admittance across the piezoelectric stack over the range of frequencies when a fluid being monitored is in the cavity, selectively receives data representing a reference electrical admittance spectra that is defined by monitoring an electrical admittance across the piezoelectric stack over the range of frequencies when the cavity is empty, selectively obtains differences of maximum values of magnitude, real values, and imaginary values between the electrical admittance spectra of the fluid and the reference electrical admittance spectra, and selectively estimates properties of the fluid by substituting values of the resonant frequency shifts into an estimator equation that was generated by, (a) comparing a number of different simulated admittance spectra with the reference admittance spectra, where each of the different simulated admittance spectra represents simulated values of admittance obtained for a particular fluid disposed in the cavity having a known density and sound speed, and where the admittance spectrum for each particular fluid is decomposed into the real, imaginary, magnitude, and phase components over a resonance frequency bandwidth, (b) developing a set of functions that include shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, the differences in shifts in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and products of shifts and differences in resonance frequencies of admittance components between each of the number of different simulated admittance spectra and reference admittance spectra, and (c) utilizing the set of functions in a series of multi-regression statistical, analyses to determine the estimator equation. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification